Pin grinding mechanism



I Nov. 23, 1965 w, DQYLE ETAL 3,219,286

PIN GRINDING MECHANISM Filed July 16, 1962 4 Sheets-Sheet 1 WM 7? Q 4- M; 7' M4 66 ii Nov. 23, 1965 w. T. DOYLE ETAL 3,219,286

PIN GRINDING MECHANISM Filed July 16, 1962 4 Sheets-Sheet 2 Nov. 23, 1965 w. T. DOYLE ETAL PIN GRINDING MECHANISM 4 Sheets-Sheet 3 Filed July 16, 1962 Nov. 23, 1965 w. T. DOYLE ETAL PIN GRINDING MECHANISM 4 Sheets-Sheet 4 Filed July 16, 1962 FIG. 5

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ATTORNEY United States Patent 3,219,286 PIN GRINDING MECHANISM William T. Doyle, Dorchester, Mass, and Austin T. Drake, Fostoria, Ohio, assignors to Sturtevant Mill Company, Dorchester, Mass, a corporation of Massachusetts Filed July 16, 1962, Ser. No. 209,861 7 Claims. 01. 241188) This application is a continuation-in-part of Serial No. 118,423 filed June 20, '1961, now abandoned.

This invention relates to a machine for grinding finely divided materials such as flour and other similar substances and in particular the invention is concerned with a grinding machine of the co-called Pin Grinding Class wherein a material to be processed i subjected to impact forces generated between rows of circumferentially spaced pins, some of which are supported in a stationary position, and others of which are supported on a revolving plate so as to pass between the stationary pins.

Conventional pin grinding machines are limited in the range of grinding which may be accomplished and such control as is realized is ordinarily carried out by increasing and decreasing the number of pins which are employed. To change the pin arrangement it has been necessary to either stop the machine or dismantle parts of it which results in loss of time and lessened output.

A further difi'iculty has also been encountered in controlling the fluidity of a stream of particles in order to carry out grinding to a desired extent and at most satisfactory grinding efliciency. Moreover, with higher pin revolving speeds there may develop an undesirable blowout of air at those points where the ground or processed material is desired to be discharged into other classifying or screening devices.

It is a chief object of the present invention to deal with the problems indicated and to devise a machine for grinding in which a more satisfactory control of grinding may be realized. Another object is to devise a pin grinding machine construction wherein the number of pins which are maintained in effective grinding relationship may be increased or decreased without interrupting the grinding operation at any time.

It is also an object of the invention to provide an adjustable pin-holding arrangement by means of which stationary grinding pins may be detachably supported in an operative position in a simplified manner. A further object is to provide a demountable pin arrangement whereby rotor pins may be removed from the machine when at rest without dismantling a cover portion of such.

machines.

We have devised special grinding pin structures, including both stationary pins and rotor pins. In the case of the stationary grinding pins, we have devised an interchangeable pin construction wherein each pin is formed with an intermediate cylindrical body portion of relatively large diameter and opposite reduced. endsof relatively small diameter. One of the reduced ends is of a length suitable for extending into the grinding passageway of the machine in the usual manner. The other reduced endis of shortened length so that it will just extend into its holder opening and no further.

By means of these two reduced pin ends, we may at any time while the machine is running, remove one or more pins as desired and insert the shortened ends of the pins so that in effect no grinding isrealized at this particular point and yet the pin aperture is completely closed.

In addition, we have provided rotor pins with special wrench socket heads so that any one of these rotor pins may be removed by means of a wrench engaged in the socket heads. There are also provided at the top of the 3,219,286 Patented Nov. 23, 1965 grinding chamber access plug means which can be removed from the machine to provide access openings for inserting a wrench without dismantling the top section of the machine.

These and other objects and novel features will be more fully understood and appreciated from the following description of preferred embodiments of the invention selected for purposes of illustration and shown in the accompanying drawings, in which:

FIGURE 1 is an elevational view of the pin grinding machine of the invention;

FIGURE 2 is another elevational view further illustrating feeding means for introducing material into the machine;

FIGURE 3 is a vertical cross sectional view taken approximately centrally of the machine and particularly illustrating the special grinding pin means of the invention;

FIGURE 4 is a plan cross section taken on the line 44 of FIGURE 3;

FIGURE 5 is a fragmentary cross sectional view showing on an enlarged scale the removable grinding pin arrangement of the invention;

FIGURE 6 is another cross sectional view showing a modified form of grinding pin arrangement;

FIGURE 7 is a fragmentary cross sectional view showing still another modified pin arrangement; and

FIGURE 8 is a fragmentary cross sectional view illustrating access plug means and installing and removing grindingpins; and

FIGURE 9 is a detail elevational view illustrating a. controlled slide element.

In carrying out the invention, we first provide for introducing particles of material into a sealed feeding device which is located at the upper side of the grinding, machine. These particles are then conducted along. two. vertically diverging paths into which paths controlled amounts of diluent air are selectively admitted to regulate the fluidity of the stream of particles delivered tothe.

grinding pin region in the machine and thereby control grinding in a novelmanner. In thus limiting flow of air. into the grinding pin region, we also find. that we are able to restrict the rate of discharge of air and ground material in a greatly improved manner. Control of grindingrealized in this way is still further regulated by means of thespecial grinding pin arrangements hereafter described in.

detail.

Referring to the structure shown. in the accompanying. drawings, numeral 2 denotes a supporting frame in. which. is mounted the pin, grinding mechanism of theinvention. including a lower casing section 4 which is formed with a bottom discharge outlet 6, and an air outlet 8, as shown in FIGURES 1 and 2. Detachably secured to the lower.

casing section 4 is an upper casing section 10. which in-- eludes an annular pin supporting plate 11 and rows of stationary pin members hereinafter described. in detail. The plate 11 extends radially outwardly. to cover or close the lower section 4 and is securely clamped thereto by means of screw clamps as suggested in FIGURES. 3 and 4.

Vertically disposed within the two casing sectiongA and 10, is a shaft 12 which is rotatably mounted in-bearings- 14 and 16 as illustrated in FIGURE 3. The shaft is pulley driven by means of a pulley 13, belts 15,.and-motor M. At the lower end of the shaft 12 is secured a rotor pin holder plate 18 which occurs-slightly below the plate 11 in substantially parallel relationship therewith to define.

an annular grinding passageway 20 and which carries rows of rotatable pins alsodescribed hereinafter in greater detail.

An important feature of the invention consists in novel'- means for handling material to be ground so that the 3 material may be brought into the machine with very carefully controlled amounts of diluent air. As noted in FIGURE 3, the upper side of the casing section has supported thereon a special feed mechanism which includes a rotary valve 22 and special conduit means commun-icating therewith. Use of this valve permits addition of particles without drawing in an undesirable quantity of air in response to the suction of the rotor pins. The conduit means consists of vertically diverging tubular parts T and T1 defining passageways as 21 and 23. A material such as flour is introduced into the top of the rotary valve 22 and is then conducted through the vertically diverging passageways 21 and 23 to a restricted annular passageway 25 and then into the casing body 10 and thence down onto the revolving plate 18. The plate 18, driven at some desired speed by means of motor M acting through the belts 15, centrifugally displaces the particles which are thus forced into the grinding passageway as has been diagrammatically indicated in FIG- URE 3. At intermediate points in the tubular members T and T1, we further provide slide valve means V and V1 as Shown in FIGURE 3 which control air inlets as H.

It will be understood that when particles are continuously fed into the rotary valve 22 and then guided through the two diverging tubular conduits T and T1 and into the restricted annular passageway as shown in FIGURE 3, the concentration or fluidity of the moving mass may increase beyond a desirable point and become sluggish. This concentration or sluggish characteristic can, we find, be desirably regulated by selectively admitting air in accordance with a predetermined setting of the slide valves and by thus controlling the concentration or fluidity of the mass, grinding action may be increased or decreased as desired.

The stationary pin members of the invention comprise two rows of stationary pin elements which are denoted as pins P1 and P2. The pins P1 and P2 are constructed with reversible end portions as may be better seen from an inspection of FIGURE 3. As noted therein each of the pins is formed with an intermediate cylindrical body portion of relatively large diameter and and two opposite reduced ends. One of the reduced ends is of a length suitable for extending into the grinding passageway 20 in the usual manner and constituting a grinding element. The other reduced end is of shortened length so that it will just extend into its holder opening with the intermediate shoulder preventing the pin from entering further to thereby constitute a hole plug.

' These pins P1 and P2 are detachably secured by clamping ring section 30. It will be apparent that by releasing the fastening the clamping ring sections 30 may be removed whereupon pins may be removed from the holding plate 11 and reversed in position to vary the impact pin surfaces within the grinding space 20. It is pointed out that this entire operation may be carried out While the machine is running and no shut-down is necessary.

In FIGURE 5 pins P1 and P2 are shown in a typical grinding position with the plug ends uppermost. In FIG- URE 8, a pin P1 is illustrated in a reversed position with the plug end engaged in the plate opening with the long end uppermost. In FIGURE 6, we have illustrated pins P3 and P4 of relatively smaller diameter to modify grinding characteristics of the machine. We may also desire to use one row of pins of relatively large size and the other row of relatively small size as indicated by the pins P5 and P6 in FIGURE 7.

I It is pointed out that in the operation of a conventional type of pin grinding machine there occurs a relatively small amount of grinding as material passes between pins at the innermost rows. The grinding action may increase very greatly, however, as the material progresses to the two outermost rows of pins and it is at these points where most of the work is done. Because of this characteristic manner of operation of the pins, it will be readily appreciated that desirable control of the degree of grinding to be carried out can be realized by using a greater or lesser number of pins in one of the outermost rows and the pin arrangement cooperates with the air control earlier described in a highly desirable manner.

In addition to the stationary pins described, we have also devised special rotor pin members which can be inserted in or removed from the rotor plate 18 without detaching the top plate 11. These rotor pins indicated by members P8, P9 and P10 are located in circumferentially spaced relation in three rows separated from one another so as to move in spaced relation to the pins P1 and P2, as shown in FIGURES 3 and 4.

As shown in FIGURE 5, we construct the upper ends of the rotor pins with recessed socket head portions P11, P12 and P13, for example, of hexagonal shape designed to receive therein an Allen wrench in snugly fitted relationship. In order to provide access for entering the wrench through the plate 11, we have further constructed this member 11 with access openings and special access plugs 40, 42, 44 which may be either threaded or smooth finished to fit in the openings as desired.

It will be apparent that by removing an access plug at any given point, a wrench may be inserted through plate 11 and a rotor pin removed from plate 18. Thereafter, the opening in plate 18 is closed by means of plugs 48, 50, 52, as suggested in FIGURE 8. The rotor pins of the invention may also be formed with the socket head portions in different diameters as suggested by pins P15, P16, P17 in FIGURE 7. In carrying out changes in pin arrangement in this way it will be observed that no dismantling of the machine need occur and a considerable saving in time and labor is realized. Thus a valuable control of grinding may be realized in a practical manner without loss of output.

Attention is directed to the fact that when the rotor pins are revolving at customary speeds in the range of 3,000 to 4,000 r.p.m., there is induced a fan-like efiect whereby suction forces act on the particles to draw them into the grinding chamber in an undesirable manner. Also the fan-like elfect can create excessive pressures on the output side with the result that blowout or discharge of ground material occurs in an objectionable manner. We have found that by controlling the consistency or concentration of the particles by means of a carefully regulated air flow, We can desirably control the grinding action of the pins and tendency to blowout on the output side.

The machine of the invention as now disclosed is intended to be utilized in processing various materials such as plastic fertilizers and various wheat products or other grains. In connection with processing grain products, the machine of the invention comprises a desirable replacement for conventional roller-mill type in some installations in flour mills. In other cases the machine of the invention may be used with excellent results to supplement roller-mill type of grinding and the processing system being desirably shortened with additional advantages of increased capacity and less overall space requirements.

The method of pin grinding described affords still other advantages, both in the operation of the machine and in the control of the product which is ground in the machine. The range of particle size can be much more sharply determined to meet with customer specification and the adaptability of the machine to change makes for a more eflicient operation.

While We have claimed a preferred form of invention, it is intended that various changes and modifications may be resorted to in keeping with the scope of the invention and defined by the appended claims.

We claim:

1. A pin grinding machine of the class described comprising a lower casing section having a discharge outlet therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing section, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, said pins being substantially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, a plurality of rotatable grinding pins vertically disposed in the pin holder plate and arranged in a circumferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly mounted in the said annular pin supporting portion, said reversible pins extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway, sealed rotary valve means for delivering material to the said feed inlet, a pair of diverging tubular feed passageways extending downwardly from the rotary sealing valve, and means for admitting selective amounts of air into the said diverging tubular feed passageway.

2. A structure according to claim 1 in which the said diverging tubular feed passageways terminate in a restricted annular passageway which communicates with the space between the upper and lower casing section.

3. A pin grinding machine of the class described comprising a lower casing section having a discharge outlet formed therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing section, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, said pins being circumferentially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, a plurality of rotatable grinding pins vertically disposed in the pin holder plate and arranged in a circumferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly received in the said annular pin supporting section, said reversible pins extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway and each of said reversible pins being formed with a grinding end, an opposite plug end, and an intermediate collar means for reversibly supporting either of said ends of the said annular pin supporting portion.

4. A pin grinding machine of the class described comprising a lower casing section having a discharge outlet formed therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing section, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, said pins being circumferentially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, a plurality of rotatable grinding pins vertically disposed in the pin holder plate and arranged in circ-umferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly received in the said annular pin supporting section, said reversible pins extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway and said reversible pins being constructed with an intermediate annular shoulder, a reversely short plug extremity extending out from the annular shoulder on one side thereof and a relatively longer grinding end extending outwardly from an opposite side of the annular shoulder, and said relatively longer grinding end being of a diameter less than the diameter of the said plug extremity.

5. A pin grinding machine of the class described comprising a lower casing section having .a discharge outlet therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing section, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, means for clamping the grinding pins in a fixed position, said pins being substantially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, 21 plurality of revolving grinding pins vertically disposed in the pin holder plate and arranged in a circumferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly mounted in the said annular pin supporting portion, said reversible pin extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway, and said pin clamping means consisting of arcuate clamping sections which extend between the inner and outer rows of projecting pin ends.

6. A pin grinding machine of the class described comprising a lower casing section having a discharge outlet therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, means for clamping the grinding pins in a fixed position, said pins being substantially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, a plurality of revolving grinding pins vertically disposed in the pin holder plate and arranged in a circumferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly mounted in the said annular pin supporting portion, said reversible pins extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway, and said rotatable pins being formed with lower end portions threaded into the lower casing section and being further formed with upper end portions recessed to provide wrench socket Openings.

7. A pin grinding machine of the class described comprising a lower casing section having a discharge outlet therein, an upper casing section formed with a feed inlet for receiving material and guiding it into the lower casing section, said upper casing section including an annular pin supporting portion which extends radially outward and which is detachably secured to the lower casing section, reversible stationary grinding pins received in the pin supporting portion, means for clamping the grinding pins in a fixed position, said pins being substantially spaced apart in inner and outer rows, each of said pins having parts thereof projecting upwardly out of the said upper casing section, a power driven shaft member, bearing means constructed and arranged in the said upper casing to support said shaft for rotation about a vertical axis, a revolving pin holder plate fixed to the shaft in parallel spaced relation below the said annular pin supporting portion to define a narrow grinding passageway, a plurality of revolving grinding pins vertically disposed in the pin holder plate and arranged in a circumferentially spaced apart manner to define a series of circular rows which occur in radially separated relationship with respect to the pin members reversibly mounted in the said annular pin supporting portion, said reversible pins extending downwardly into the narrow grinding passageway between the revolving pins and cooperating therewith to exert a grinding action on materials passing through the narrow passageway and said rotatable pins being formed with lower end portions threaded into the lower casing section and being further formed with upper end portions recessed to provide wrench socket openings, said upper casing section being formed with pin withdrawal apertures arranged to register with the rotatable pins in one position of rotation through which disengaged wrench supported pins may be withdrawn to vary the grinding capability of the machine.

References Cited by the Examiner UNITED STATES PATENTS 143,336 9/1873 Cutler 241-188 1,215,424 2/ 1917 Spensley 241188 1,272,473 7/ 1918 Lombard.

1,446,151 2/ 1923 Blyth.

1,576,472 3/ 1926 Riley.

1,621,869 3/1927 Bryant 241-27 2,428,670 10/1947 Hulse 241-188 3,001,727 9/1961 Block et al. 241-9 FOREIGN PATENTS 642,904 5/ 1928 France.

677,365 6/1939 Germany.

689,936 2/1951 Great Britain.

1. SPENCER OVERHOLSER, Primary Examiner.

ROBERT A. OLEARY, Examiner. 

3. A PIN GRINDING MACHINE OF THE CLASS DESCRIBED COMPRISING A LOWER CASING SECTION HAVING A DISCHARGE FORMED THEREIN, AN UPPER CASING SECTION FORMED WITH A FEED INLET FOR RECEIVING MATERIAL AND GUIDING IT INTO THE LOWER CASING SECTION, SAID UPPER CASING SEDTION INCLUDING AN ANNULAR PIN SUPPORTING PORTION WHICH EXTENDS RADIALLY OUTWARD AND WHICH IS DETACHABLY SECURED TO THE LOWER CASING SECTION, REVERSIBLE STATIONARY GRINDING PINS RECEIVED IN THE PIN SUPPORTING PORTION, SAID PINS BEING CIRCUMFERENTIALLY SPACED APART IN INNER AND OUTER ROWS, EACH OF SAID PINS HAVING PARTS THEREOF PROJECTING UPWARDLY OUT OF THE SAID UPPER CASING SECTION, A POWER DRIVEN SHAFT MEMBER, BEARING MEANS CONSTRUCTED AND ARRANGED IN THE SAID UPPER CASING TO SUPPORT SAID SHAFT FOR ROTATION ABOUT A VERTICAL AXIS, A REVOLVING PIN HOLDER PLATE FIXED TO THE SHAFT IN PARALLEL SPACED RELATION BELOW THE SAID ANNULAR PIN SUPPORTING PORTION TO DEFINER A NARROW GRINDING PASSAGEWAY, A PLURALITY OF ROTATABLE GRINDING PINS VERTICALLY DISPOSED IN THE PIN HOLDER PLATE AND ARRANGED IN A CIRCUMFERENTIALLY SPACED APART MANNER TO DEFINE A SERIES OF DIRCULAR ROWS WHICH OCCUR IN RADIALLY SEPARATED RELATIONSHIP WITH RESPECT 